Im getting really stressed with my 07 reg 1.9 tdi ambiante octavia. We had car serviced 3 months ago a month later the water coolant light came on & water coolant low opened cap and water came back up and topped up slightly. Took car to skoda dealer and they explained it was time for a new water pump and cam belt so had that done by a friend mechanic as was cheaper. 2 weeks later light came back on :OS so took it back to garage and thought it could only be the header tank as there isnt any coolant mixed in oil in engine plus its not over heating so replaced header tank and cap.....then.......light cam back on other day :o/ so today had a pressure test done which connects to header tank and had 20 psi pushed through it with no pressure being released anywhere so no leaks... im completely stuck and really need some kind of help please if you can xxx